1. Field of the Invention
The present invention is directed generally to containers and more particularly to single or multi-dose vented containers used to ship liquids requiring ventilation.
2. Description of the Invention Background
In certain types of precision equipment, the liquid dispensed into the equipment must be of high quality and/or precise quantity. To achieve those goals, manufacturers often provide cartridges or containers containing liquid of the desired quality and quantity. However, containers or cartridges which can be refilled by the user are susceptible of being refilled with improper quality or imprecise quantities of liquids. For example, in some hydrogen peroxide sterilization systems, it is necessary to use hydrogen peroxide within a limited concentration range. A more concentrated solution of hydrogen peroxide can be hazardous and a less concentrated solution might be ineffective to achieve sterilization under the conditions present in the particular sterilization system. A technician, unaware of the importance of using a particular type of hydrogen peroxide or other liquid, might refill a liquid container with the incorrect type or volume of liquid.
In addition, continuous reuse of containers tends to contaminate the container. Hydrogen peroxide solutions will degrade into water and oxygen in the presence of certain contaminants resulting in a less concentrated solution which may be ineffective for its intended use. Moreover, if the container is sealed, the buildup of oxygen upon liquid degradation will pressurize the container, perhaps causing the container to burst.
In U.S. Pat. No. 4,941,519 entitled "Liquid Feed System Using A Non-reusable Container" issued Jul. 17, 1990, a solution is provided to the aforementioned problems. Disclosed in that patent is a non-reusable container used in conjunction with a connection member and a cam member. Operation of the cam member forces the connection member downward into fluid communication with the container. Thereafter, fluid can be removed from the container via a dip tube which extends nearly to the bottom of the container. After all of the fluid has been removed, the cam member is again actuated which causes the vent tube/dip tube to be pushed down dislodging it from the cartridge cap rendering the container non-reusable. With the dip tube thus forced into a position in which it can no longer be used to withdraw liquid from the container, the container is not suited to be refilled and reused.
Another example of a sterilant concentration injection system is disclosed in U.S. Pat. No. 5,037,623. The apparatus disclosed in that patent provides an arm/needle configuration which punctures a single-dose cartridge. The cartridge is comprised of a vent passage defining a vent aperture at a first end which is in fluid communication with the exterior of the cartridge. The vent aperture is disposed centrally in three dimensions in the interior volume such that when fluid partially fills the interior volume, the vent aperture remains in the head space of the fluid regardless of the orientation of the cartridge.
Although the cartridge of U.S. Pat. No. 5,037,623 is vented in all orientations of the cartridge, the cartridge is used in a system in which liquid flows through the cartridge. For other types of systems in which the liquid within the cartridge is withdrawn from the cartridge, the thus-spent cartridge requires special handling because of potential residuals left in the cartridge. Thus, the need exists for a non-reusable, vented cartridge capable of dispensing exact amounts of a known quantity of fluid, which, upon being spent, presents no disposal problems.